usr/src/lib/lvm/libsvm/common/getdrvname.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <ctype.h>
  31 #include <string.h>
  32 #include <limits.h>
  33 #include <sys/types.h>
  34 #include <svm.h>
  35
  36 /*
  37  *      Macros to produce a quoted string containing the value of a
  38  *      preprocessor macro. For example, if SIZE is defined to be 256,
  39  *      VAL2STR(SIZE) is "256". This is used to construct format
  40  *      strings for scanf-family functions below.
  41  */
  42 #define QUOTE(x)        #x
  43 #define VAL2STR(x)      QUOTE(x)
  44
  45 static int is_blank(char *);
  46
  47 /*
  48  * is_blank() returns 1 (true) if a line specified is composed of
  49  * whitespace characters only. otherwise, it returns 0 (false).
  50  *
  51  * Note. the argument (line) must be null-terminated.
  52  */
  53 static int
  54 is_blank(char *line)
  55 {
  56         for (/* nothing */; *line != '\0'; line++)
  57                 if (!isspace(*line))
  58                         return (0);
  59         return (1);
  60 }
  61
  62 /*
  63  * FUNCTION:
  64  *      Return the driver name for a major number
  65  *
  66  * INPUT: major number, mount point for name_to_major file, pointer
  67  * to a valid buffer.
  68  *
  69  * RETURN VALUES:
  70  *      0 - SUCCESS - buf contain the driver name.
  71  *      -1 - FAIL
  72  *
  73  */
  74
  75 int
  76 get_drv_name(major_t major, char *mnt, char *buf)
  77 {
  78         FILE *fp;
  79         char drv[FILENAME_MAX + 1];
  80         char entry[FILENAME_MAX + 1];
  81         char line[MAX_N2M_ALIAS_LINE], *cp;
  82         char fname[PATH_MAX];
  83
  84         int status = RET_NOERROR;
  85         (void) snprintf(fname, sizeof (fname), "%s%s", mnt, NAME_TO_MAJOR);
  86
  87         if ((fp = fopen(fname, "r")) == NULL) {
  88                 return (RET_ERROR);
  89         }
  90
  91         while ((fgets(line, sizeof (line), fp) != NULL) &&
  92                                                 status == RET_NOERROR) {
  93                 /* cut off comments starting with '#' */
  94                 if ((cp = strchr(line, '#')) != NULL)
  95                         *cp = '\0';
  96                 /* ignore comment or blank lines */
  97                 if (is_blank(line))
  98                         continue;
  99                 /* sanity-check */
 100                 if (sscanf(line,
 101                     "%" VAL2STR(FILENAME_MAX) "s %" VAL2STR(FILENAME_MAX) "s",
 102                     drv, entry) != 2) {
 103                         status = RET_ERROR;
 104                 }
 105                 if (atoi(entry) == major)
 106                         break;
 107         }
 108
 109         if (status == RET_NOERROR)
 110                 (void) strcpy(buf, drv);
 111         (void) fclose(fp);
 112         return (status);
 113 }